The Reactions of Two New Alkoxy-silyl Functionalized Alkynes with M<Subscript>3</Subscript>(CO)<Subscript>12</Subscript> {M = Fe,Ru} and Co<Subscript>2</Subscript>(CO)<Subscript>8</Subscript>. Spectroscopic Identification of the Products

The new alkoxysilyl-functionalized alkynes [HC≡CCH₂N(H)C(=O)N(H)(CH₂)₃Si(OEt)₃] and [HC≡C(C₆H₄)–N(H)C(=O)N(H)(CH₂)₃Si(OEt)₃] have been synthesized using literature methods. These have been reacted with Fe₃(CO)₁₂, Ru₃(CO)₁₂ and Co₂(CO)₈. With the iron carbonyl only decomposition was observed: with Ru₃(CO)₁₂ splitting of the alkynes into their parent components and formation of the complexes (μ-H)Ru₃(CO)₉[HC=N(CH₂)₃Si(OEt)₃], (μ-H)Ru₃(CO)₉[C–C(C₆H₄)NH₂] and (μ-H)₂Ru₃(CO)₉[HC–CCH₃] occurred. Finally, with Co₂(CO)₈ formation of complexes Co₂(CO)₆(HC₂R) R=(C₆H₄)NH₂, CH₂NH(CO)NH(CH₂)₃Si(OEt)₃, (C₆H₄)NH(CO)NH(CH₂)₃Si(OEt)₃ containing the intact alkynes could be obtained.     

Phase equilibria in binary subsystems of urea–biuret–water system

Joint results of the differential scanning calorimetry (DSC) and thermogravimetry (TG) experiments were the basis for the fusion enthalpy and temperature determination of the biuret (NH₂CO)₂NH (synthesis by-product of the urea fertilizer (NH₂)₂CO). Recommended values are Δ_m H = (26.1 ± 0.5) kJ mol⁻¹, T _m = (473.8 ± 0.4) K. The DSC method allowed for the phase diagrams of “water–biuret,” “water–urea,” “urea–biuret” binary systems to be studied; as a result, liquidus and solidus curves were precisely defined. Stoichiometry and decomposition temperature of the biuret hydrate identified, composition of the compound in “urea–biuret” system was suggested.     

Heterometallic “butterfly” cluster [Fe3(CO)9(μ3-OBut)Au(PPh3)]

Alkylation of the [Fe₃(μ₃-O)(CO)₉]²⁻ dianion withtert-butyl iodide afforded the [Fe₃(μ₃OBu¹)(CO)₉]⁻ monoanion. The reaction of the latter with Au(PPh₃)Cl in the presence of TIBF₄ yielded the new heterometallic “butterfly” cluster [Fe₃(CO)₉(μ₃-OBu^t)Au(PPh₃)]. According to the X-ray data, both clusters synthesized contain the unchanged Fe₃(μ₃-O) fragment of the initial dianion. The addition of the Au(PPh₃) fragment to the monoanion occurred in such a way as to minimize steric changes. As a result, a “turned inside out” heterometallic “butterfly”, which contains the μ₃-O ligand on the outside rather than on the inside, was obtained. The dihedral angle characterizing the “butterfly” is 151°. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1779–1783, September, 1999.     

Synthesis, spectroscopic, and structural aspects of two trinuclear cyano-bridged heterometallic complexes

Two new cyano-bridged trinuclear heterometallic complexes [Sr₂(Phen)₄(CF₃CO₂)(H₂O)₃Fe(CN)₆]·2H₂O (1) [Ca₂(Phen)₄(CF₃CO₂)(H₂O)Co(CN)₆]·2H₂O (2) (where Phen=1,10-phenanthroline) have been synthesized and their crystal structures have been determined. The structure of complex (1) features a central [Fe(CN)₆]³⁻ unit that links a monocation, [Sr(Phen)₂(OH₂)(OOCCF₃)]⁺ and a dication, [Sr(Phen)₂(OH₂)₂]²⁺ via two trans cyanide bridges. The complex (2) features a central [Co(CN)₆]³⁻ unit that links two monocations of [Ca(Phen)₂(OH₂)(OOCCF₃)]⁺ (the positions of the trifluoro acetate and water molecules are disordered over two positions) via two trans cyanide bridges. Each metal atom is seven coordinated and achieves pentagonal bipyramidal geometry. Two cocrystallized water molecules are present in both the complexes. The presence of an extensive network of hydrogen bonding imparts the overall stability to both the systems.     

Pivalates with the M<Superscript>II</Superscript><Subscript>4</Subscript>O<Subscript>4</Subscript> cubane core (M = Co,Ni): synthesis,structure, magnetic properties,and solid-state thermolysis

Methods were developed for the controlled thermal synthesis of high-spin cubane-like pivalates {M^II ₄(μ₃−OR)₄} (M = Co or Ni; R = H or Me) starting from mono-and polynuclear complexes. The solid-state thermal decomposition of the known pivalate clusters [M^II ₄(μ₃−OMe)₄−(μ₂−OOCBu^t)₂(η²−OOCBu^t)₂(MeOH)₄] and the new clusters [M₄^II(μ₃)−OH₄(η¹−OOCBu^t)₃−(μ−(NH₂)₂C₆H₂Me₂)₃(η¹−(NH₂)₂C₆H₂Me₂)₃]⁺(OOCBu^t)− (M = Co or Ni) was studied by differential scanning calorimetry and thermogravimetry. The thermolysis of cubane-like CoII and NiII pivalates is a destructive process. The phase composition of the decomposition products is determined by the nature of coordinated ligands and the structural features of the metal core.     

New Cyclosiloxanolate Cluster Complexes of Transition Metals

New cyclosiloxanolate transition metal cluster complex derivatives were prepared. PhSiO₂K reacted with NiX₂ (X₂ = Cl₂ or acac) to give K₂{[η⁶−(PhSiO₂)₆]₂[μ₃−(OH)]₂Ni₄K₄}, a mixed group 1–group 10 metal complex. PhSiO₂Na reacted with Ni(NH₃)₆I₂ to give Na{[η⁶−(PhSiO₂)₆]₂Ni₆(μ₆−I)} as the first example of “encapsulated” I⁻ ion in siloxanolate complexes. The macrocyclic Na₄{[η¹²−(PhSiO₂)₁₂]Cu₄} complex reacted with η⁶−(1,3,5−C₇H₈)Cr(CO)₃ to give the heterobimetallic adduct Na₄{[η¹²−(PhSiO₂)₁₂]Cu₄}· [Cr(CO)₃]₃ as one of the rare examples of heterobimetallic complexes with different oxidation numbers of the metals. The copper derivative {[η⁶−(PhSiO₂)₆]₂Cu₆(n−BuOH)₅} reacted in MeOH/CHCl₃ (1:6) with Et₄NCN to give the hexanuclear complex {[η⁶−(PhSiO₂)₆]₂Cu₆(η²−C₃H₅N₂O₂)₂}, containing 2-amino-2-oxoetanimidic acid methyl ester monoanion ligands, product of an unexpected C–C coupling reaction. This latter complex was characterized also by X-ray diffraction crystal and molecular structure determination. This paper is dedicated to the 70th birthday of Professor Dr. Gunter Schmid (Essen), pioneer of large cluster chemistry, known to friends as GOLD-Schmid, because of his famous discovery of the Au₅₅ cluster. The Authors are proud to be within his many friends.     

Formation of Alkyne Bridged Multicobalt Carbonyl Complexes with Tris(2‐Thienyl)Phosphine or Bis(Trimethylsilylethynyl)Phenylphosphine Ligand

Treatment of Co₄(CO)₁₂ with an excess of trimethylsilylacetylene (TMSA) in the presence of tri(2‐thienyl)phosphine in THF at 25 °C for 2 hours yielded six compounds. Two pseudo‐octahedral, alkyne‐bridged tetracobalt clusters, [Co₄(μ₄‐η²‐HC≡CSiMe₃)(CO)₁₀(μ‐CO)₂] ( 4 ) and [Co₄(μ₄‐η²‐HC≡CSiMe³)‐(CO)₉(μ‐CO)₂{P(C₄H₄S)₃}] ( 6 ), along with an alkyne‐bridged dicobalt complex, [Co₂(CO)₅(μ‐HC≡CSiMe₃)‐{P(C₄H₄S)₃}] ( 5 ), were obtained as new compounds. The addition of the thienylphosphine ligand, in fact, facilitates the reaction rate. Reaction of an alkyne‐bridged dicobalt complex, [(η²‐H‐C≡C‐SiMe₃)Co₂(CO)₆] ( 3 ), with a bi‐functional ligand, PPh(‐C≡C‐SiMe₃)₂, yielded an unexpected six‐membered, cyclic compound, {(Ph)(Me₃Si‐C≡C)P‐[(η²‐C≡C‐SiMe₃)Co₂(CO)₅]}₂ ( 7 ). All of these new compounds were characterized by spectroscopic means; the solid‐state structures of ( 5 ), ( 6 ) and ( 7 ) have been established by X‐ray crystallography.     

Thermolyse von Cyanokomplexen. VII. Über die Thermischen Zersetzungsreaktionen der Hexacyanokobalte(III); Ligandenumlagerungen bei der Thermolyse

Thermolysis of cyano complexes. VII. On the thermal decomposition of hexacyanocobaltate(III); ligand exchange during thermolysis The thermal decomposition of hexacyanocobaltates(III) yields, as products of successive intramolecular redox reactions, first dicyan and Co^II(Co^III)-complexes, then Co^II[Co^II]-complexes and simple Co^II(CN)₂, respectively, and finally Co^ICN and elemental Co, respectively. All the compounds of the [Co^III(NH₃)₆]³⁺ cation with the cyanometallate anions of Co, Fe, Cr, Mn, Ni, Mo yield the same DTA curve as [Co(NH₃)₆][Co(CN)₆] does; in the case of Ni and Cr, which are capable of forming ammine complexes, simultaneous mutual ligand exchange occurs.     

Kinetic and mechanistic studies on the electron-transfer reactions between diaquabisethylenediaminecobalt(III) and ethylenediaminetetraacetatocobaltate(III) with promazine in acidic aqueous media

The kinetics of the electron-transfer reactions between promazine (ptz) and [Co(en)₂(H₂O)₂]³⁺ in CF₃SO₃H solution ([Co^III] = (2–6) × 10⁻³ m, [ptz] = 2.5 × 10⁻⁴ m, [H⁺] = 0.02 − 0.05 m, I = 0.1 m (H⁺, K⁺, CF₃SO ₃ ⁻ ), T = 288–308 K) and [Co(edta)]⁻ in aqueous HCl ([Co^III] = (1 − 4) × 10⁻³ m, [ptz] = 1 × 10⁻⁴ m, [H⁺] = 0.1 − 0.5 m, I = 1.0 m (H⁺, Na⁺, Cl⁻), T = 313 − 333 K) were studied under the condition of excess Co^III using u.v.–vis. spectroscopy. The reactions produce a Co^II species and a stable cationic radical. A linear dependence of the pseudo-first-order rate constant (k _obs) on [Co^III] with a non-zero intercept was established for both redox processes. The rate of reaction with the [Co(en)₂(H₂O)₂]³⁺ ion was found to be independent of [H⁺]. In the case of the [Co(edta)]⁻ ion, the k _obs dependence on [H⁺] was linear and the increasing [H⁺] accelerates the rate of the outer-sphere electron-transfer reaction. The activation parameters were calculated as follows: ΔH ^≠ = 105 ± 4 kJ mol⁻¹, ΔS ^≠ = 93 ± 11 J K⁻¹mol⁻¹ for [Co(en)₂(H₂O)₂]³⁺; ΔH ^≠ = 67 ± 9 kJ mol⁻¹, ΔS ^≠ = − 54 ± 28 J K⁻¹mol⁻¹ for [Co(edta)]⁻.     

Reactions of conjugated dienes with cobalt carbonyls under hydroformylation conditions. a high pressure i.r. spectroscopic study

Summary The chemistry of cobalt carbonyls in the presence of dienes and high pressure of synthesis gas was studied by online i.r. spectroscopy. Dicobalt octacarbonyl reacts with butadiene under 95 bar CO/H₂ and 80°C to give [³-C₄H₇Co(CO)₃] (1) and [⁴-C₄H₆)₂Co₂(CO)₄] (2). Hydrogenation or hydroformylation are observed only with [HCo(CO)₄] as the starting catalyst, and only at the beginning of the reaction. The results are explained by formation of an alkenyl complex, [-C₄H₇Co(CO)₄], which either reacts with [HCo(CO)₄] to give butene and [Co₂(CO)₈], or loses CO to give (1), depending on the [HCo(CO)₄] concentration. The butene is hydroformylated. At temperatures >100°C (1) is transformed into a CO-free species, which catalyzes the oligomerisation of butadiene. Addition of tributylphosphine (L) leads to the formation of [³-C₄H₇Co(CO)₂L] (5) and [Co₂(CO)₆L₂] (6). In (5) the -allyl moiety is more labile than in (1) and a slow hydrogenation and hydroformylation of the butadiene is observed. In methanol solution the reaction of the cobalt carbonyls to give (1) is incomplete and the remaining H⁺ and [Co(CO)₄]^– catalyze the hydroformylation of butadiene. Isoprene is less reactive than butadiene but otherwise behaves similarly.     

Synthesis of poly-yne polymer containing platinum and silicon atoms in the main chain by oxidative coupling and its reactions with transition-metal carbonyl complexes

The platinum poly-yne polymer, [? C?C? SiMe₂? C?C? Pt(PBu₃)₂? C?C? SiMe₂? C?C? ]_n (2), was synthesized by the oxidative coupling of a silicon–platinum monomer, trans-(PBu₃)₂Pt(C?C? SiMe₂–C?CH)₂ (1). The reaction of platinum poly-yne polymer 2 with dicobaltoctacarbonyl gave μ-coordinated complexes, {[? C?C? SiMe₂? C?C? Pt(PBu₃)₂? C?C? SiMe₂? C?C? ] [Co₂(Co)₆]₂}_n (4). the electric conductivity of iodine adducts of the polymer complexes 4 was 3.0×10^?5 S cm^?1. As an aid to spectroscopic characterization of the polymer complex 4, a model complex, {trans-[(PBu₃)₂Pt? (C?C? SiMe₂? C?CH)₂]} {[Co₂(CO)₆]₂} (3), was also prepared by the reaction of 1 with dicobaltocatacarbonyl. Selective coordination of Co₂(CO)₆ groups to ? SiMe₂? C?C C?C? Si(Me)₂? Moieties and coordinative inertness of the Pt? C?C? moieties were confirmed by comparison of the NMR spectra of 3 with those of 4. All new compounds have been characterized by analytical and spectral analysis (IR, ¹H NMR).     

Ring Opening and Bidentate Coordination of Amidinate Germylenes and Silylenes on Carbonyl Dicobalt Complexes: The Importance of a Slight Difference in Ligand Volume

The reactions of [Co₂(CO)₈] with one equiv of the benzamidinate (R₂bzam) group‐14 tetrylenes [M(R₂bzam)(HMDS)] (HMDS=N(SiMe₃)₂; 1 : M=Ge, R=iPr; 2 : M=Si, R=tBu; 3 : M=Ge, R=tBu) at 20 °C led to the monosubstituted complexes [Co₂{κ¹M?M(R₂bzam)(HMDS)}(CO)₇] ( 4 : M=Ge, R=iPr; 5 : M=Si, R=tBu; 6 : M=Ge, R=tBu), which contain a terminal κ¹M–tetrylene ligand. Whereas the Co₂Si and Co₂Ge tert‐butyl derivatives 5 and 6 are stable at 20 °C, the Co₂Ge isopropyl derivative 4 evolved to the ligand‐bridged derivative [Co₂{μ‐κ²Ge,N‐Ge(iPr₂bzam)(HMDS)}(μ‐CO)(CO)₅] ( 7 ), in which the Ge atom spans the Co?Co bond and one arm of the amidinate fragment is attached to a Co atom. The mechanism of this reaction has been modeled with the help of DFT calculations, which have also demonstrated that the transformation of amidinate‐tetrylene ligands on the dicobalt framework is negligibly influenced by the nature of the group‐14 metal atom (Si or Ge) but is strongly dependent upon the volume of the amidinate N?R groups. The disubstituted derivatives [Co₂{κ¹M?M(R₂bzam)(HMDS)}₂(CO)₆] ( 8 : M=Ge, R=iPr; 9 : M=Si, R=tBu; 10 : M=Ge, R=tBu), which contain two terminal κ¹M–tetrylene ligands, have been prepared by treating [Co₂(CO)₈] with two equiv of 1 – 3 at 20 °C. The IR spectra of 8 – 10 have shown that the basicity of germylenes 1 and 3 is very high (comparable to that of trialkylphosphanes and 1,3‐diarylimidazol‐2‐ylidenes), whereas that of silylene 2 is even higher.     

Mono-and polynuclear CoII complexes with 2-hydroxy-6-methylpyridine

The reaction of 2-hydroxy-6-methylpyridine with Co(NO₃)₂·6H₂O or Co(F₃CSO₃)₂·6H₂O in the absence of a deprotonating agent produces the mononuclear complexes Co(HL)₄(NO₃)₂ or Co(HL)₄(F₃CSO₃)₂ (HL is 6-methyl-2-pyridone), respectively. In the presence of triethylamine, the reaction affords the trinuclear complex Co₃(HL)₂(L)₄(NO₃)₂ or the heptanuclear dicationic complex [Co₇L₁₂]·(F₃CSO₃)₂·4MeCN in the case of cobalt nitrate or cobalt trifluoromethanesulfonate, respectively. When HL is deficient, the replacement of the trimethylacetate anions in polymeric cobalt pivalate [Co(OH)_n(OOCCMe₃)_2−n ]_x gives rise to the hexanuclear complex Co₆(μ₃-OH)₂(η²,μ₃-L)₂(μ-OOCCMe₃)₈(HOOCCMe₃)₄, whereas the HLCo₆(μ₃-OH)(η²,μ₃-L)₃(η²,μ-L) (μ₃-L)(μ₃-OOCCMe₃)(μ-OOCCMe₃)₄(η²-OOCCMe₃) complex is generated when HL is present in excess. The structures of the reaction products were established by X-ray diffraction. Dedicated to Academician O. M. Nefedov on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1851–1862, November, 2006.     

Molecular Design of Polyoxometalate-Based Compounds for Environmentally-Friendly Functional Group Transformations: From Molecular Catalysts to Heterogeneous Catalysts

This review article summarizes our recent researches for molecular design of polyoxometalates (POMs) and their related compounds for environmentally-friendly functional group transformations. The divacant POM [γ-SiW₁₀O₃₄(H₂O)₂]⁴⁻ exhibits high catalytic performance for mono-oxygenation-type reactions including epoxidation of olefins and allylic alcohols, sulfoxidation, and hydroxylation of organosilanes with H₂O₂. We have successfully synthesized several POM-based molecular catalysts (metal-substituted POMs) with controlled active sites by the introduction of metal species into the divacant POM as a “structural motif”. These molecular catalysts can efficiently activate H₂O₂ (vanadium-substituted POM for epoxidation) and alkynes (copper-substituted POM for click reaction and oxidative homocoupling of alkynes). The aluminum-substituted POM exhibits Lewis acidic catalysis for diastereoselective cyclization of (+)-citronellal to (−)-isopulegol. In addition, we have developed POM-based “molecular heterogeneous catalysts” by the “solidification” and “immobilization” of catalytically active POMs.     

Outer-Sphere electron-transfer and the effect of linkage isomerism in the titanium(III) reduction of nitro-pentacyanocobaltate(III) and nitro-, and nitrito-pentaamminecobalt(III) complexes in aqueous acidic media

The reductions of [Co(CN)₅NO₂]³⁻, [Co(NH₃)₅NO₂]²⁺ and [Co(NH₃)₅ONO]²⁺, by Ti^III in aqueous acidic solution have been studied spectrophotometrically. Kinetic studies were carried out using conventional techniques at an ionic strength of 1.0 mol dm⁻³ (LiCl/HCl) at 25.0 ± 0.1 °C and acid concentrations between 0.015 and 0.100 mol dm⁻³. The second-order rate constant is inverse—acid dependent and is described by the limiting rate law:- k₂ ≈ k₀ + k[H⁺]⁻¹,where k=k′K_a and K_a is the hydrolytic equilibrium constant for [Ti(H₂O)₆]³⁺. Values of k₀ obtained for [Co(CN)₅NO₂]³⁻, [Co(NH₃)₅NO₂]²⁺ and [Co(NH₃)₅ONO]²⁺ are (1.31 ± 0.05) × 10⁻² dm³ mol⁻¹ s⁻¹, (4.53 ± 0.08) × 10⁻² dm³ mol⁻¹ s⁻¹ and (1.7 ± 0.08) × 10⁻² dm³ mol⁻¹ s⁻¹ respectively, while the corresponding k′ values from reductions by TiOH²⁺ are 10.27 ± 0.45 dm³ mol⁻¹ s⁻¹, 14.99 ± 0.70 dm³ mol⁻¹ s⁻¹ and 17.93 ± 0.78 dm³ mol⁻¹ s⁻¹ respectively. Values of K _a obtained for the three complexes lie in the range (1–2) × 10⁻³ mol dm⁻³ which suggest an outer-sphere mechanism.     

Synthesis and structure of cobalt α-dioximate complexes with isonicotinamide

New cobalt trans-dioximate complexes with isoniconinamide have been synthesized: [Co^II(DmgH)₂(Inia)₂] (I), [Co^III(DmgH)₂(Inia)₂][PF₆] · 1.5H₂O (II), [Co^III(NioxH)₂ (Inia)₂][PF₆] · H₂O · CH₃OH (III), and [CoIIICl(DmgH)₂(Inia)] · H₂O (IV), where DmgH⁻ and NioxH⁻ are the dimeth-ylglyoxime and 1,2-cyclohexanedionedioxime monoanions, respectively; Inia is the isonicotinamide molecule. The structures of compounds I–IV have been determined by X-ray crystallography. In I–IV, Co(II) or Co(III) has an octahedral environment with the pseudomacrocyclic (DioxH⁻)₂ moiety (DioxH⁻ is the dioximate monoanion) in the equatorial plane. The latter is stabilized by O-H…O hydrogen bonds. The isonicotinamide molecules in all four complexes are monodentately bound to the metal ion through the heterocyclic nitrogen atom.     

A joint electrochemical/spectroelectrochemical inspection (and re-inspection) of high-nuclearity platinum carbonyl clusters

The accurate study of the electron transfer activity of the tetraanion [Pt₁₉(CO)₂₂]⁴⁻ is presented together with that of the dianion [Pt₃₈(CO)₄₄]²⁻, which was previously studied by spectroelectrochemistry but only partially examined from the electrochemical viewpoint. The main feature of the two clusters is that they undergo a sequence of close-spaced pairs of reversible one-electron processes, which are qualitatively reminiscent of those exhibited by the dianion [Pt₂₄(CO)₃₀]²⁻. In order to focus on such unique aspect of the three structurally characterised platinum clusters, we have investigated (and reinvestigated) their electrochemical and spectroelectrochemical redox properties, also reporting on the electron paramagnetic resonance (EPR) spectrum of the monoanion [Pt₂₄(CO)₃₀]⁻, which represents the first successful study of the paramagnetism of homoleptic platinum–carbonyl clusters.     

Theoretical investigation on hydroformylation reactions : I. Structures and reactivities of cobalt carbonyls and hydrocarbonyls

Extended Hückel Theory calculations have been carried out in a study of the most important cobalt carbonyls and hydrocarbonyls involved in the hydroformylation reaction. The geometries of the stable isomers of Co₂(CO)₈, Co₂(CO)₇, Co(CO)₄, Co(CO)₃ have been calculated and used to interpret the changes in the IR spectrum of Co₂(CO)₈ observed on varying the temperature. The reaction paths for the interconversions of the stable isomers have also been investigated. The optimized geometry of HCo(CO)₄ agrees well with the experimental structure. The C_s symmetry found for the most stable isomer of HCo(CO)₃ is of much interest, serves to explain the formation of the complex with olefins.     

Carbonylate anion [(μ-H)Os<Subscript>3</Subscript>(CO)<Subscript>10</Subscript>L]<Superscript>−</Superscript> as a precursor in the synthesis of heterometallic Os<Subscript>3</Subscript>M clusters

A new method for the synthesis of heterometallic clusters Os₃M is developed. The reactions of hydridocarbonyl cluster (μ-H)₂Os₃(CO)₁₀ (I) with binuclear carbonyls Co₂(CO)₈ and Fe₂(CO)₉ in the presence of 1,4-diazabicyclo[2.2.2]octane (Dabco) afford anionic complexes [Os₃Co(CO)₁₃]⁻ (II) and [HOs₃Fe(CO)₁₃] (III) with the counterion N₂C₆H₁₃⁺. Similar reactions with halide complexes [MCp*Cl₂]₂ (M = Rh and Ir) yield neutral complexes [Os₃M(CO)₁₀(μ-H)(μ-Cl)] (M = Rh(IV) and Ir(V)). The reactions occur rapidly at room temperature with high yields. The newly obtained clusters are characterized by the data of IR and ¹H NMR spectroscopy, elemental analysis, and X-ray diffraction analysis.     

Structure of complex salts [Co(NH3)6][Rh(NO2)6] and [Co(NH3)6][(NO2)3Rh(μ-NO2)1+x(μ-OH)2?xRh(NO2)3]·(2-x)(H2O), x = 0.17

The structures of two salts [Co(NH₃)₆][Rh(NO₂)₆] (I) and [Co(NH₃)₆][(NO₂)₃Rh(μ-NO₂)_1+x (μ-OH)_2−x Rh(NO₂)₃]·(2−x)(H₂O), x = 0.17 (II) are solved. Single crystals of the salts are obtained by the counter diffusion method through the gel of aqueous solutions of [Co(NH₃)₆]Cl₃ and Na₃[Rh(NO₂)₆]. The structure of [Co(NH₃)₆][Rh(NO₂)₆] is consistent with the diffraction data for a polycrystalline sample of poorly soluble fine salt formed in the exchange reaction between aqueous solutions of [Co(NH₃)₆]Cl₃ and Na₃[Rh(NO₂)₆]. The structure of [Co(NH₃)₆][(NO₂)₃Rh(μ-NO₂)_1+x (μ-OH)_2−x Rh(NO₂)₃]·(2−x)(H₂O), x = 0.17 exhibits the stabilizing effect of a large cation in the formation of novel, unknown previously coordination ions: [(NO₂)₃Rh(μ-NO₂)(μ-OH)₂Rh(NO₂)₃]³⁻ and [(NO₂)₃Rh(μ-NO₂)₂(μ-OH)Rh(NO₂)₃]³⁻.